Every open workers' compensation claim carries a number that most employers never look at closely: the reserve. It is not what the claim has cost. It is what the carrier expects the claim to cost before it closes. And for as long as the claim is open, that expectation flows into your experience modifier and, through it, into what you pay for coverage.
This is a plain-language explanation of how reserves work, why they matter more than most employers realize, and what you can reasonably do about them.
What a reserve actually is
When a claim is opened, the adjuster estimates the total cost of the claim from first report to closure. That estimate is the reserve. It has two main parts:
Medical. Doctor visits, imaging, physical therapy, surgery, prescriptions, and anything else needed to treat the injury.
Indemnity. Wage replacement while the employee is off work or on restricted duty, plus any permanent disability award if the injury leaves lasting impairment.
Some carriers also reserve separately for expense: legal fees, independent medical examinations, surveillance, and similar costs. On the loss run you receive from your carrier, you may see these broken out, or you may see one combined figure.
The reserve is set early, often within the first few weeks, when the adjuster has the least information. It is then adjusted as the claim develops. A claim that looked like a two-week strain and turns into a surgery will have its reserve raised. A claim that resolves faster than expected should have its reserve lowered.
Should, but not always does. That gap is where employers get hurt.
Why the reserve matters before the claim closes
Your experience modifier is calculated from your loss history. It uses incurred losses, and incurred means paid plus reserved. A claim with $4,000 paid and a $40,000 reserve counts as a $44,000 loss in your experience rating, even though only $4,000 has left anyone's account.
The experience rating window generally covers three policy years, ending one year before the mod takes effect. So a claim opened this year will sit in your rating data for roughly three renewals. If its reserve is high during any of the snapshots the rating bureau takes, the mod reflects that high number, whether or not the claim ever actually costs that much.
This is why claims professionals talk about reserve adequacy in both directions. Under-reserving is a problem for the carrier. Over-reserving, or a reserve that stays high after the claim has clearly moved past its worst case, is a problem for you.
What "adequate" looks like
There is no single right reserve. Two adjusters can look at the same claim and set different numbers, and both can be defensible. But a reserve should be consistent with what is actually happening on the claim:
- The employee's current work status. Back at full duty, on restrictions, or off work.
- The treatment plan and where the employee is in it.
- Whether the treating physician has projected maximum medical improvement.
- Whether an attorney is involved.
- The typical cost of similar injuries in your state, which rating bureaus and research organizations publish.
When the reserve and the facts have drifted apart, that is the moment to ask about it.
What you can do
You cannot set reserves. That is the carrier's job, and the adjuster's judgment carries weight. What you can do is be the employer who notices.
Read your loss run. Ask your carrier or TPA for it at least quarterly. Look at every open claim's reserve, and look at how it has changed since the last run.
Know your own facts. You know when the employee came back to work, whether modified duty was offered and accepted, and what the treating physician said. If the reserve still reflects an employee who is off work and that employee has been back for two months, you have something concrete to raise.
Ask, don't argue. A note to the adjuster that says "Our records show this employee returned to full duty on March 3. Can you walk me through the current reserve?" is the right register. It is a question, it is specific, and it is easy to answer.
Track the answer. If the reserve comes down, note the date. If it doesn't, note the explanation. Either way you now have a record, and your next renewal conversation with your broker starts from facts rather than a number on a page.
Time it to the rating snapshot. Your rating bureau values your claims on a schedule tied to your policy date. Reserve conversations that happen a month before that snapshot matter more than ones that happen a month after. Your broker or carrier can tell you when your data is valued.
The point
The reserve is the carrier's estimate. Your experience modifier treats it as fact. The employer who reads the loss run, knows the claim, and asks the right question at the right time is the employer whose mod reflects what actually happened rather than what someone guessed might happen.
That is what it means to participate in your own program.